A woman charged with the attempted murder of her son allegedly watched him being beaten unconscious without trying to intervene, a court heard today.

Police also claimed Julie Larsen cleaned up after Matthew Larsen was attacked with a metal bar at a flat in the Mount Vernon area of north Belfast.

The 24-year-old victim was struck up to 20 times after an initial blow to the head caused his ear to “explode”, a judge was told. He is currently in intensive care at the Royal Victoria Hospital being treated for critical injuries allegedly inflicted on Monday.

Julie Larsen, 41, of Ross House in Mount Vernon, faces charges of attempted murder and attempting to pervert the course of justice. She is further accused of causing grievous bodily harm to another woman at the scene.

As she appeared before Belfast Magistrates’ Court an investigating detective said the charges were brought on the basis of a joint enterprise. A man suspected of actually carrying out the attack on her son is still at large.

The lawyer added: “We believe Mrs Larsen had arrived at the flat knowing that the other suspect was going to seriously assault her son. Then, after the assault, she proceeded to clean up the flat and make it look as if the assault had occurred somewhere else.”

She allegedly tried to mislead police by saying she found her son in the state he was in, and that he had been under threat from locals. The man still being sought by police is believed to have threatened others at the scene, the court heard.

According to the detective Julie Larsen witnessed the “sustained attack” on her son but made no attempt to stop it. It was also claimed that she spoke of him deserving the beating said to have been carried out with a drop bar similar to the type used to barricade doors.

During cross-examination the officer confirmed Larsen had denied the offences during interviews. She is not accused of taking part in the physical assault on her son, the court heard.

But police alleged that she knew he was going to be subjected to violence, having arrived around seven minutes before an ambulance was called. Based on witness accounts, the detective said: “The victim was struck on the head with a drop bar once, causing his ear to explode. He was then struck approximately 20 more times.”

When Mr Larsen’s partner tried to stop the attack she was also hit, breaking her arm in three places, it was alleged. A defence lawyer challenged police claims that Julie Larsen saw the attack take place or tried to mislead the investigation.

It was stressed that she had been the one to administer first aid and then went to the hospital. Seeking bail, the solicitor added: “It’s obviously desperately tragic circumstances in relation to this man’s injuries. Her main concern is her son and his critical condition.”

However, District Judge Ken Nixon refused to release Larsen based on the risk of interference with witnesses. She was remanded in custody to appear again by video-link in a week’s time.